New research criteria for the diagnosis of Alzheimer's disease applied in a memory clinic population

Abstract

Background: In the newly proposed research criteria for Alzheimer's disease (AD), patients are defined as having memory dysfunction in addition to either hippocampal atrophy or an abnormal cerebrospinal fluid (CSF) profile. This study applies the criteria in a memory clinic population, using clinical criteria as the reference criterion.

Methods: 138 AD patients, 145 nondemented subjects, 78 patients with other dementias and 91 patients with mild cognitive impairment (MCI) were included. Dichotomized medial temporal lobe atrophy (MTA) score on MRI and dichotomized CSF profiles (based on beta-amyloid1-42, tau and phosphorylated tau at threonine 181 levels) were used in combination with an episodic memory test to assess sensitivity, specificity and likelihood ratios (LR) of the newly proposed criteria and their components separately.

Results: We found specificities of 95 and 49% for comparison with nondemented subjects and other demented patients, respectively, with a sensitivity of 86% for AD. Specificity was highest (100 and 77%, respectively, LR+ = 48) when both MTA score and CSF profile were abnormal in addition to the episodic memory test, at the cost of a low sensitivity (48%).

Conclusion: The newly proposed research criteria for AD yield a good specificity for comparison with nondemented subjects. When the type of dementia is clinically doubted, however, at least two supportive features should be considered (i.e. abnormal MTA score and CSF profile) in addition to memory impairment as core diagnostic criterion.